This invention relates to a device for use in a flexible disk cartridge that is adapted to be placed in a disk drive of a computer system and a method of manufacturing the device. More particularly, the present invention concerns a shutter for covering the head window opening in the protective case that contains the flexible disk and a method of manufacturing the shutter.
The three and one-half inch flexible disk cartridge for storing information includes a flexible circular disk having a magnetic coating on both sides and a case that surrounds and encloses the disk. The case has two oppositely positioned head window openings through which the flexible disk is exposed. In order to cover the head window openings and thereby protect the flexible disk when the cartridge is not positioned in the disk drive, a spring biased shutter is provided.
The American National Standards Institute, Inc. has published a standard that has been agreed upon by a majority of those individuals having a direct and materially affected interest in the three and one-half inch flexible disk cartridge. The standard is referred to as American National Standard X3.137-1988 and is incorporated herein by reference.
The aforementioned standard sets forth specifications regarding the dimensions of the case, the materials from which the various parts of the flexible disk cartridge should be manufactured as well as the physical and other relevant properties that the various parts should possess.
The use of the three and one-half inch flexible disk cartridge has become quite widespread and consequently the number of flexible disk cartridges manufactured and sold is very large. The manufacture and sale of shutters for use in the flexible disk cartridge has experienced a similar growth. In view of the large number of shutters that are manufactured and sold, it can be readily seen that any cost savings attributable to the manufacture of each individual shutter will result in a very large overall cost savings.
Similarly, since the shutter accounts for a significant portion of the total cost associated with the manufacture of the flexible disk cartridge, any cost savings associated with the manufacture of each individual shutter will result in lower costs for the manufacture of the flexible disk cartridge as a whole. Those cost savings may, in turn, be passed on to the consumer so that the cost of purchasing a flexible disk cartridge is reduced.
From the foregoing discussion, it is apparent that it would be highly desirable to manufacture shutters by using less material and/or less expensive material. The manufacture of thinner shutters or smaller shutters would permit the aforementioned objectives to be achieved by significantly reducing the material costs. Similarly, the use of different materials that are less expensive than those commonly used would result in substantial savings in material costs.
Another concern that arises in the manufacture of shutters for use in the three and one-half inch flexible disk cartridge concerns the manner in which the shutters are packaged after they have been manufactured. Typically, the shutters are formed by passing a sheet of material through a stamping die and subjecting the sheet of material to repeated stamping or punching operations. The stamping or punching operations result in the manufacture of individual shutters which are then packaged in containers for shipment to the customers.
A problem arises in such a manufacturing and packaging process in that the individual shutters are free to contact each other in the container in which they are packaged. The shutters are subjected to repeated jostling and contact with each other throughout the package handling and shipping stages and that can result in damage to the shutters. In particular, the precision formed edges of the shutters can be damaged as a result of the continuous contact between the shutters in the container. Further, any coating that may be located on the shutters for protective or performance purposes can be easily damaged through repeated contact with other shutters. The damage suffered by the shutters as a result of the aforementioned manufacturing and packaging process may adversely affect the performance of the shutter and in some cases, may necessitate that the shutters be discarded.
It can be seen, therefore, that there exists a need for a different process for manufacturing and packaging the shutters in order to avoid the problems associated with the process currently used.
The aforementioned problems are overcome and the foregoing objectives are achieved by the shutter and the method for manufacturing the shutter in accordance with the present invention. The shutter includes a piece of material having first and second substantially rectangular portions and an intermediate portion that connects the first and second portions to one another. The first and second portions each have two substantially parallel first sides and two substantially parallel second sides. The first sides of the first and second portions are longer than the second sides of the first and second portions. The first and second portions each have a substantially rectangular opening located therein that is defined by two substantially parallel first sides and two substantially parallel second sides. The two first sides in each opening are longer than the two second sides and the two first sides in each opening are substantially parallel to the second sides of the first and second portions. One of the first sides of the opening in the first portion and one of the first sides of the opening in the second portion are coplanar and the other first side of the opening in the first portion and the other first side of the opening in the second portion are coplanar. The distance between the second sides of the first and second portions in a direction perpendicular to the second sides is equal to or less than 1.630 inches. Further, the thickness of the shutter is equal to or less than 0.007 inches. The shutter can be manufactured from stainless steel, plated brass, pre-plated steel, aluminum or copper-based material.
In another embodiment of the present invention, the shutter includes an outwardly extending flange that is integrally connected to a second side of the intermediate portion and a substantially L-shaped tab that is integrally connected to the flange. One end of a spring member is adapted to be positioned between the flange and the L-shaped tab in order to seat the spring member and thereby bias the shutter in the closed position.
According to another aspect of the present invention, the shutters are arranged in a wound roll. Each of the shutters includes a piece of material having first and second substantially rectangular portions and an intermediate portion that connects the first and second portions to one another. The first and second portions each have two substantially parallel first sides and two substantially parallel second sides. The first sides of the first and second portions are longer than the second sides of the first and second portions. The first and second portions each have a substantially rectangular opening located therein that is defined by two substantially parallel first sides and two substantially parallel second sides. The two first sides in each opening are longer than the two second sides and the two first sides of each opening are substantially parallel to the second sides of the first and second portions. One of the first sides of the opening in the first portion and one of the first sides of the opening in the second portion are coplanar and the other first side of the opening in the first portion and the other first side of the opening in the second portion are coplanar. Additionally, a connecting arrangement is provided for connecting adjacent ones of the shutters.
In one embodiment, the first and second portions of each shutter are substantially parallel and lie in different planes and the connecting arrangement includes a strip of material that connects the intermediate portions of adjacent shutters. In another embodiment, the first and second portions of each shutter are substantially parallel and lie in different planes and the connecting arrangement includes a plurality of strips of material that connect one of the first sides of the first portion of one shutter to one of the first sides of the first portion of an adjacent shutter. In a further embodiment of the present invention, the first and second portions of each shutter are partially folded and the connecting arrangement includes a strip of connecting material that extends between adjacent shutters. In a still further embodiment, the first and second portions of each shutter are coplanar and the connecting arrangement includes a strip of material that connects one of the second sides of the first portion of one shutter to one of the second sides of the first portion of an adjacent shutter and a strip of material that connects one of the second sides of the second portion of the one shutter to one of the second sides of the second portion of the adjacent shutter.
According to a further aspect of the present invention, a method of manufacturing the shutters includes feeding a sheet of material to a stamping die and punching the sheet of material with the die to form a plurality of connected shutters such that the shutters include first and second substantially rectangular portions and an intermediate portion that connects the first and second portions to one another. The first and second portions each have two substantially parallel first sides and two substantially parallel second sides. The first sides of the first and second portions are longer than the second sides of the first and second portions. The first and second portions each have a substantially rectangular opening located therein that is defined by two substantially parallel first sides and two substantially parallel second sides. The two first sides in each opening are longer than the two second sides and the two first sides of each opening are substantially parallel to the second sides of the first and second portions. One of the first sides of the opening in the first portion is coplanar with one of the first sides in the second portion and the other first side of the opening in the first portion is coplanar with the other first side in the second portion. The method further includes the step of winding the connected shutters into a roll.